We start this week with 26.2 miles of courage and heart and a spirit that stretches across a whole nation. Boston strong. A triumph ant marathon victory today. You'll remember a year ago four people died. But today we watch athletes prove there is no such thing as disabled. And a Po ittic code. American man, the first to win the marathon since 1983. ABC was right there. Reporter: For the 36,000 runners -- nine more than last year. And one million spectators -- double the average. Today was about sending a message -- you can knock us down, but not for long. We had to show as individuals. As a city, as a community, really as a nation that we're not afraid. Reporter: They stopped running and started helping people. Today they were returning again under the watchful eye of 4,000 cops on the streets. On the roofs and in the sky. Why is it important to you to run again this year? We didn't finish what we set out to do and didn't feel right. Reporter: It was an American who won today for the first time since 1985. An American will win the Boston marathon. Reporter: His name is meb keflezighi. He's 38. Became a U.S. Citizen in 1998 and today wore the names of the four people who died in the attacks. On his official runners bib. Some of the survivors bravely returned to the finish line today including Jeff Baumann from this iconic shot in the moments after he lost his legs and was rescued by a stranger in a cow bboy hat. There he was today with friend Carlos. Heather Abbott was here, too, who lost her lower left leg. She ran the last half mile alongside a woman who helped save her life that day. We're not going to let anybody stop us. Reporter: As the day wore on, there were quite justifiably a few wobbly finishers. But not Natalie and Joe, they finally fcrossed the finish line. Reporter: I think it's safe to say you guys took the marathon back. Yes they did. And president Obama weighing in on saying all of today's runners showed the world the true meaning of Boston strong. I couldn't agree more, Diane. All in all, a very, very good day in my hometown. Great to have them taking their day back. Now, next to the incredible

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